A Reciprocity Approach for Computing the Response of Wiring Systems to Diffuse Electromagnetic Fields

This paper is concerned with the problem of computing the response of a wiring system to a high frequency, short wavelength, electromagnetic field, such as that which can arise in the interior of an irradiated vehicle. It is shown that a “diffuse-field reciprocity principle” developed recently in the field of vibroacoustics can be applied to electromagnetic systems, thus, enabling the currents induced in a wiring system by diffuse electromagnetic waves to be computed in an efficient manner. With this approach only the radiation characteristics of the wiring system are required to be computed; more specifically, the impedance matrix associated with radiation into an infinite dielectric is required, and an efficient method of computing this matrix is given in the present paper, based on exact solutions to Maxwell's equations. Initially, the diffuse-field reciprocity principle is proved explicitly for one- and two-wire systems, and the method is then applied to numerical examples involving these systems. The applicability of diffuse-field theory to high-frequency interior reverberant electromagnetic fields has been verified analytically and experimentally in recent years, and this paper offers the possibility of exploiting these developments to avoid large-scale electromagnetic compatibility computations.